derivative market losses starting to emerge, page-2

hi yc
i have seen this derivative issue mentioned a couple of times now but i dont really understand what it means. it reminds me of july07 when subprime became a new word in my dictionary.
i have seen numbnuts numbers regarding the exposure some banks have in the der. market, in the trillions.
and apparently this is the reason why some are predicting meltdown. could u express the issue in laymans terms, or anyone?

thanks